Soil series profile

Carsitas soil series

Carsitas is a somewhat excessively drained soil with a loamy sand surface, mapped on 415,382 acres in 5 counties across 2 states. Hydrologic group A.

#740 by mapped area Typic Torripsamments (Entisols)

Drainage class: Somewhat excessively drained
Hydrologic group: A
Typical topsoil pH: 8.0
Mapped area: 415k

Typical Carsitas profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Carsitas horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–1 in (A)	Loamy sand	7.8	5%	80%	0.25%
1–6 in (Bw)	Sandy loam	7.8	6%	65%	0.12%
6–47 in (C1)	Gravelly sand	8.1	3%	87%	0.12%
47–59 in (C2)	Gravelly sand	8.1	3%	87%	0.12%

Representative values from the most extensive Carsitas map unit (Carsitas-Chemwash complex, 2 to 4 percent slopes, survey area CA803). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Carsitas soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Carsitas soils is moderately alkaline: pH 8.0 (most land between 7.6 and 8.2). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).

Sandy topsoil covers 97% of mapped Carsitas acres. It drains fast and warms early in spring, but dries out and loses nutrients quickly: mulch, compost and steady watering help. The most common surface texture is loamy sand (25% of mapped Carsitas acres).

97% of mapped Carsitas acres is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.

For lawns and yards

92% of mapped acres is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.

For a septic system

For conventional septic absorption fields, NRCS rates 85% of the acres in mapped Carsitas soils very limited, 3% somewhat limited and 9% not limited (3% not rated, such as urban land, pits or water).

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Flooding is mapped on 16% of the acres (5% occasional, 2% frequent).

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Carsitas soil is found

Mapped acres

Carsitas is mapped in California and Arizona.

Counties with the most mapped Carsitas soil
County	Acres	Share of county land
Riverside County, CA	138,055	4.6%
Imperial County, CA	15,599	1.1%
San Bernardino County, CA	7,684	0.1%
Maricopa County, AZ	5,895	0.1%
San Diego County, CA	5,043	0.2%

Septic absorption fields

NRCS rating, share of Carsitas acres

Not limited 9%

Somewhat limited 3%

Very limited 85%

Not rated 3%

Septic tank absorption field rating across mapped Carsitas acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Carsitas acres.
Category	Share of acres
Not limited	8.7%
Somewhat limited	3.4%
Very limited	85.1%
Not rated	2.7%

Drainage, water table and flooding

Share of Carsitas acres

Depth to seasonal high water table: About 2.9 feet (35 in) (median where reported).
Flooding: Mapped as flooding on 16% of acres (5% occasional, 2% frequent).
Slope: Typically 2–6% (median 3%).
Topsoil organic matter: Median 0.3%.

Drainage class

Excessively drained 21%

Somewhat excessively drained 75%

Well drained <1%

Moderately well drained 0%

Somewhat poorly drained <1%

Poorly drained 0%

Very poorly drained 0%

Not rated 3%

Drainage class across mapped Carsitas acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Carsitas acres.
Category	Share of acres
Excessively drained	21.4%
Somewhat excessively drained	75.1%
Well drained	0.1%
Moderately well drained	0.0%
Somewhat poorly drained	0.7%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	2.7%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 92%

B: moderate infiltration 4%

C: slow infiltration <1%

D: very slow infiltration (clayey, shallow or wet) 0%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Not rated 3%

Hydrologic soil group across mapped Carsitas acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Carsitas acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	92.3%
B: moderate infiltration	4.3%
C: slow infiltration	0.7%
D: very slow infiltration (clayey, shallow or wet)	0.0%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%
Not rated	2.7%

Sources & data dates

Source: USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date: SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope: All map unit components named Carsitas (component kind "Series") in SSURGO: 415,382 acres.
Method: Shares are by mapped acres of Carsitas components. The profile comes from the single largest Carsitas component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Carsitas.